Southampton researchers double silicon speed record

Add a dash of fluorine for extra whizz

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Engineers at the University of Southampton have set a new world speed record for silicon performance by adding a little fluorine to the mix.

By implanting standard silicon with the element, the researchers were able to double the current record and extract transit frequency (fT) of 110GHz from the humble bipolar transistor.

Previously, this kind of performance was only possible with silicon germanium.

"By using fluorine implants, the transistor can operate at a higher frequency which means it will be twice as fast as it was before," said Professor Peter Ashburn, who led the research at the university's school of Electronics and Computer Science.

"This means that the electronics industry will be able to achieve better performance at little extra cost."

The trick works because the fluorine implantation suppresses boron diffusion in the base of the transistor. This means the base width is narrower and electrons can move across it more quickly.

Professor Ashburn and his team are confident that boron diffusion can be suppressed further - by as much as another 50 per cent. They are currently investigating other materials that could perform as the fluorine does. ®